- Email: [email protected]
Serial magnetization transfer imaging in acute optic neuritis
tion transfer sequence. Twenty-one had multiple subsequent examinations over the course of 1 year. In addition, 27 control subjects had their optic nerves imaged up to three times over 1 year. A blinded observer segmented the optic nerves from the MTR maps. Lesions were defined on the acute FSE images and, from the coordinates, the ratio of mean lesion MTR : healthy nerve MTR (lesion ratio) was calculated for each dataset. The time-averaged mean MTR in control optic nerves was 47.7 per cent units (pu). In diseased optic nerves, baseline mean MTR was 47.3 pu, with a mean lesion ratio of 0.98. The diseased optic nerve MTR and lesion ratio declined over time with a nadir at about 240 days at a mean MTR value of 44.2 pu and mean lesion ratio of 0.91. After 1 year the diseased optic nerve mean MTR was 45.1 pu (mean lesion ratio 0.93), although the difference was not significant compared with the nadir value. For each 0.01 increase in time-averaged lesion ratio logMAR visual acuity recovery improved by 0.03 (95% CI, 0.002, 0.08, P ⫽ 0.02). Time-averaged VEP central field latency was shorter by 6.1 ms (95% CI 1.5, 10.7, P ⫽ 0.012) per 1 pu rise in time-averaged diseased optic nerve MTR. The authors conclude that early fall in diseased optic nerve MTR is consistent with demyelination and Wallerian degeneration of transected axons. The late nadir compared with studies of multiple sclerosis lesions may have been due to slow clearance of myelin debris. Remyelination may have influenced subsequent MTR changes. The observations support using MTR to monitor symptomatic demyelinating lesions.—Vale´ rie Biousse
*Institute of Histology and Embryology, Medical Faculty, University of Ljubljana, Korytkova 2, 1105 Ljubljana, Slovenia; e-mail: [email protected]
●
Clinical and immunohistochemical evidence for an X linked retinitis pigmentosa syndrome with recurrent infections and hearing loss in association with an RPGR mutation. Iannaccone A,* Breuer DK, Wang XF, Kuo SF, Normando EM, Filippova E, Baldi A, Hiriyanna S, MacDonald CB, Baldi F, Cosgrove D, Morton CC, Swaroop A, Jablonski MM. J Med Genet 2003;40:118.
T
HE AUTHORS REPORT A FAMILY WITH X LINKED RECES-
sive retinitis pigmentosa (RP) associated with the unique phenotype of relapsing otitis media (ROM), recurrent upper respiratory tract infections (RUTI), and hearing loss, in which a G173R missense mutation in the RPBR gene was identified. In addition to classical RP in males and late onset mild patchy RP with a cone⬎rod pattern of dysfunction in carriers, audiometry showed mixed hearing loss in affected males with ROM and RUTI, and sensorineural loss in a female carrier who had also suffered from ROM. Using immunohistochemistry, the authors demonstrated specific RPGR expression in the epithelial lining of the sinuses, bronchi and cochlea. These findings provide additional evidence in favor of a broader phenotypic range in association with RPGR mutations than previously unsuspected and suggest an important role for RPBR in the respiratory tract and cochlea.—Hans E. Grossniklaus *University of Tennessee Health Science Center, Department of Ophthalmology, 956 Court Avenue, Suite D228, Memphis, TN; e-mail: [email protected]
*Pr D.H. Miller, NMR Research Unit, Department of Neuroinflammation, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK; e-mail: [email protected]
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Serial magnetization transfer imaging in acute optic neuritis. Hickman SJ, Toosy AT, Jones SJ, Altmann DR, Miszkiel KA, MacManus DG, Barker GJ, Plant GT, Thompson AJ, Miller DH.* Brain 2004;127:692–700.
M
● Eye movement and visuomotor arm movement deficits following mild closed head injury. Heitger MH,* Anderson TJ, Jones RD, Dalrymple-Alford JC, Frampton CM, Ardagh MW. Brain 2004;127:575–590.
AGNETIZATION TRANSFER IMAGING (MT) ALLOWS
T
the examination of tissues in more details than conventional MRI. In serial studies of multiple sclerosis lesions, reductions in magnetization transfer ratio (MTR) are thought to be due to demyelination and axonal loss, with later rises due to remyelination. In this study, the authors followed serial changes in MTR in acute optic neuritis in combination with clinical and electrophysiological measurements to determine if the MTR changes over time mirror the picture in multiple sclerosis lesions. They included 29 patients who had acute optic neuritis for a median of 13 days (range 7–24 days) since the onset of visual symptoms. A clinical examination and measurement of visual evoked potentials (VEP) was performed on each patient. Their optic nerves were imaged with a fatsaturated fast spin echo (FSE) sequence and a magnetiza-
1172
AMERICAN JOURNAL
HERE IS INCREASING EVIDENCE THAT EVEN MILD
closed head injury (CHI) can cause considerable neural damage throughout the brain, in the form of either focal lesions or diffuse axonal injury. Indeed, a large proportion of mild CHI patients experience disabling persistent post-concussional complaints. At 6 months post-injury, approximately 30% of mild CHI patients meet the criteria for the diagnosis of post-concussion syndrome. None of the initial measures of trauma severity are able to predict the development of post-concussion syndrome. The authors hypothesized that mild CHI will disrupt the complex cerebral networks concerned with oculomotor and upper-limb visuomotor control, resulting in impaired motor function. They compared 30 patients with recent mild CHI (defined as Glasgow Coma Scale 13–15, alter-
OF
OPHTHALMOLOGY
JUNE 2004
*Institute of Histology and Embryology, Medical Faculty, University of Ljubljana, Korytkova 2, 1105 Ljubljana, Slovenia; e-mail: [email protected]
●
Clinical and immunohistochemical evidence for an X linked retinitis pigmentosa syndrome with recurrent infections and hearing loss in association with an RPGR mutation. Iannaccone A,* Breuer DK, Wang XF, Kuo SF, Normando EM, Filippova E, Baldi A, Hiriyanna S, MacDonald CB, Baldi F, Cosgrove D, Morton CC, Swaroop A, Jablonski MM. J Med Genet 2003;40:118.
T
HE AUTHORS REPORT A FAMILY WITH X LINKED RECES-
sive retinitis pigmentosa (RP) associated with the unique phenotype of relapsing otitis media (ROM), recurrent upper respiratory tract infections (RUTI), and hearing loss, in which a G173R missense mutation in the RPBR gene was identified. In addition to classical RP in males and late onset mild patchy RP with a cone⬎rod pattern of dysfunction in carriers, audiometry showed mixed hearing loss in affected males with ROM and RUTI, and sensorineural loss in a female carrier who had also suffered from ROM. Using immunohistochemistry, the authors demonstrated specific RPGR expression in the epithelial lining of the sinuses, bronchi and cochlea. These findings provide additional evidence in favor of a broader phenotypic range in association with RPGR mutations than previously unsuspected and suggest an important role for RPBR in the respiratory tract and cochlea.—Hans E. Grossniklaus *University of Tennessee Health Science Center, Department of Ophthalmology, 956 Court Avenue, Suite D228, Memphis, TN; e-mail: [email protected]
*Pr D.H. Miller, NMR Research Unit, Department of Neuroinflammation, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK; e-mail: [email protected]
●
Serial magnetization transfer imaging in acute optic neuritis. Hickman SJ, Toosy AT, Jones SJ, Altmann DR, Miszkiel KA, MacManus DG, Barker GJ, Plant GT, Thompson AJ, Miller DH.* Brain 2004;127:692–700.
M
● Eye movement and visuomotor arm movement deficits following mild closed head injury. Heitger MH,* Anderson TJ, Jones RD, Dalrymple-Alford JC, Frampton CM, Ardagh MW. Brain 2004;127:575–590.
AGNETIZATION TRANSFER IMAGING (MT) ALLOWS
T
the examination of tissues in more details than conventional MRI. In serial studies of multiple sclerosis lesions, reductions in magnetization transfer ratio (MTR) are thought to be due to demyelination and axonal loss, with later rises due to remyelination. In this study, the authors followed serial changes in MTR in acute optic neuritis in combination with clinical and electrophysiological measurements to determine if the MTR changes over time mirror the picture in multiple sclerosis lesions. They included 29 patients who had acute optic neuritis for a median of 13 days (range 7–24 days) since the onset of visual symptoms. A clinical examination and measurement of visual evoked potentials (VEP) was performed on each patient. Their optic nerves were imaged with a fatsaturated fast spin echo (FSE) sequence and a magnetiza-
1172
AMERICAN JOURNAL
HERE IS INCREASING EVIDENCE THAT EVEN MILD
closed head injury (CHI) can cause considerable neural damage throughout the brain, in the form of either focal lesions or diffuse axonal injury. Indeed, a large proportion of mild CHI patients experience disabling persistent post-concussional complaints. At 6 months post-injury, approximately 30% of mild CHI patients meet the criteria for the diagnosis of post-concussion syndrome. None of the initial measures of trauma severity are able to predict the development of post-concussion syndrome. The authors hypothesized that mild CHI will disrupt the complex cerebral networks concerned with oculomotor and upper-limb visuomotor control, resulting in impaired motor function. They compared 30 patients with recent mild CHI (defined as Glasgow Coma Scale 13–15, alter-
OF
OPHTHALMOLOGY
JUNE 2004